Electric heating device



ELECTRIC HEATING .DEVICE 2 3 rm-11 ci- 2,

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2 ma di @my e n u j ELECTRIC HEATING DEVICE Filed March 28, 1922 2 Shees-$hee 2 Patented June 26, 1923a WALTER c. LINDEMANN, or

MILWAUKEE, WISCONSIN, ASSIGNOR TU A.. J. LINDE- MANN & HOVERSON COMPANY, GF MILWAUKEE, WISCONSIN.

ELECTRIC HEATING DEVICE.

Application filed March 28, 1922. Serial No. 547,585.

T o all. whom it may concern Be it known that I, WALTER C. LINDE- MANN, a citizen of the United States, and a resident of the city of Milwaukee, in the county of Milwaukee, State of lWisconsin,

have invented certain new and useful Improvements in Electric Heating Devices, of which the following is a specification.

The improvements relate to electrical heating devices, for cooking or other purposes, and particularly to devices of this kind in which grids or plates with openings therein are employed to support cooking utensils, food, or other thingsto be subjected to the heat of electric resistance elements arranged beneath the grid. Among the objects of the improvements are the production of a construction having greater strength, durability and heating eiciency, and 1n which the parts may be assembled or' dismembered for repairs or other purposes with facility, and may be made in various forms. Another and more specific object is to so form and arrange the frame of the heating unit and its insulators, by which the electric resistance heating element is held, that they maybe manufac- .tured by methods calculated to produce a simple, strong, and effective unit at a minimum manufacturing cost, and treated before being assembled, to resist the action of heat, electric current and uids to which ,they are subjected in use.

The improvements are illustrated in the accompanying-drawings, inwhich Figure 1 is'Y a plan of a heating unit embodying the improvements; Fig. 2 :is a vertical section of the same on the line. 2--2 of Fig. l, looking in the direction indicated by the 0 arrows in that figure; Fig. 3 is a view similar to Fig. 2 of metallic'frame with the insulating and heat .ing element holders removed; Fig. is a detail of one of the parts an insulating holder; Fig. 5 is a plan of a modified form; 6 is a vertical section of the same on the line 2-2 of 5, looking in the direction indicated by the arrows in that figure, and Fig. 'i' is a vertical section of 52 modified form of holder.

Referring to the construction illustrated in rigs. 'l to 4; inclusive, the frame of the heating unit comprises a plate l, in which.' is formed centrally a or comu the upper part of thev posed of a .central portion 2 with arms or webs 3 radiating therefrom, concentric rings 4 and 5 and connecting webs 6 and 7 between these rings and between the outer one and the plate 1. It yfalso has flanges 8 depending from its edges adapted to receive and hold thesimilar upstanding ianges- 9 of the bottom plate 10, thereby forming a boxlike enclosure for the other parts. The lower plate of the frame or casing ma be provided with suitable feet, if desire and is of the same form as the upper plate, both plates being preferably stamped to produce the grid.

In making the two halves of the housing it is preferred to take a sheet of metal and stamp and punch it by means ofsuitable dies, so as to form the sides thereof and the openings of the grid; and in this operation a suiicient quantity of the metal is permitted to remain along the edges of the openings to form not only the too and bottom grid members but to form` in the stamping operation, depending ianges 11, 12, 13, 11, 15, 1c, 17, 18, 19, 2o, 21, 25, ete., at the edges of said members. which not only serve to add great strength and durability, but form holders to receive half blocks 22. 22a forming the insulating support Jfor the electric resistance elements 23 and 24. At the corners the flanges may be cut away as shown at 30 to facilitate the stamping operation.

The blocks 22. 22a are made of porcelain or other suitable electric insulating substance, and are relatively light but strong and of suiicient width to space and insulate the resistance elements, while at the same time they absorb a minimum of heat and permit a maximum of the heat of the said element to be utilized'for cooking or heating operations. The electric resistance elements 23 and 24 extend through the apyertures 26 of .the insulating and supporting 'blocks composed of the two complemental parts 22. 22a and span the spaces of grid, being connected with service wires means of binding posts 2T, 2G, and 29, having electrical Contact devices thei n@langes 8 and 9 have open slots for the binding posts.

The two parts of the housing, including 'the grids, as will be seen, are each made of a single piece o1? sheet metal, and, bef-ore lil@ sembling these parts may be coated with vitreous enamel or other suitable protective coating.

For units designed to be used with low temperature resistance elements the flanges of the grid members may be made longer and curled at their lower edges, as shown at 31 (Fig. 7), so as to form a holder with an aperture 32 to receive the .said element, where the construction of the grid and the disposition of the resistance element permit it. In any case the said resistance element may be coiled, crimped or shaped in any suitable mannerto produce the desired result.

In the modification of Figs. 5, 6, and T the grid is of rectangular form, and the longitudinal flanges 34 of the grid bars 33 receive and hold insulating supports 35 eX- tending longitudinally thereof and supporting resistance wires 36, these supports having a plurality 0f recesses, which, when the two halves of the support are placed together, form wire-receiving apertures 37. Bolts 38 may be passed through the upper and lower plates 39 and 40 of this form, as well as through the plates of the preferred form, if desired, to hold them securely together. The form of resistance element support shown in Fig. 7 is peculiarly applicable to this modification, but where the wires are run crosswise through the support it will be necessary to form longitudinal complemental recesses therein similar in form to those ofthe supports 35, so as to produce apertures for the said wires.

In assembling the unit the bottom member of the housing is first made up by placing half blocks in the holding flanges. The electric resistance.element is then laid in the recesses of the blocks and the upper half with its half blocks then placed thereon and cured. In disassembling the unit this operation may be reversed; and it will be seen that the construction and arrangement is such that the unit may be taken apart for the purpose of cleaning it or renewing the wires or other parts and put together again quickly and with a small expenditure of labor.

The top or bottom membe of the housing, or both, may, if desired,' e cast instead of stamped, and may be made of any suitable material, and the details of construction and arrangement of the parts may be varied to a certain extent without departing from the scope of the invention.

at I claim is:

1. An electric heating unit comprising upper and lower sections forming a housing for the unit, each part provided with a portion of a resistance element supporting and insulating device, upper and lower insulating device partsv supported in said housing parts, each having a recess therein, and the two recesses formed to produce when brought opposite each other apertures for receiving a resistance element` and a resistance element in said apertures and supported by the insulating device, and means for securing the said upper and lower parts together.

I2. In a device such as that specified in claim 1, holding flanges extending from each housing part toward' the other and 0pposed to each other, said flanges being arranged in spaced relation lto receive the said insulatin parts.

3. A device such as that specified in claims 1 and v2, in which the flanges are integral with their respective housing parts.

4. In a device such as that specified in claim Lengaging portions on the upper and lower housing parts constructed' and arranged to ltelescope when the said parts are brought together.

5. A device such as that specified in claim l, having openings in the said housing parts formed by punching out the metal thereof having strips between them forming a grid, and a portion of the metal displaced in forming said' openings turned inwardly and forming insulator holding flanges.

6. A device such as that specified in claim` l, in which the upfper and lower housing parts are formed o flat sheets` of material punched and stampedto form therein grids having relatively large openings and strips of material between them and the edges of said openings turned inwardly7 to form strengthening flanges depend'in" therefrom, and forming holders` for the insulating device.

7. In a device such as that specified in claim 1, a coating of vitreous material on the upper surface of theupper housing part.

8. An electric heating unit comprising a metal form having upper and lowersections secured together, an electric resistance heatin element between said sections, and insulating holders for said element secured in place by and between said sections, said sections having grid openings therein and -depending flangesat theedges of grid openings.

9. In combination with the mechanism specified in claim 8, a coating of vitreous enamel applied' to one of said sections and covering t e surfaces of the same.

10. In the device specified in claim 8, the said flanges projecting inwardly from said sections and receiving and holding` said insulating holders.

11. In the device specified in claim 8, the said flanges formed of metal displaced by punching and stamping the metal of one of the sections, said flanges receiving and' holding insulating holders.

12. In the device .specified in claim 8, the said flanges extending inwardly from grid lforming openings with which one of said sections is provided, said anges being integral with the metal at the edges of said openin and securing the insulating holders.

13. electric heating unit comprising a metal form having upper and lower sections secured together, an electric resistance heatin element between said sections, and insulatln holders for said element secured in place y and between said sections, said insulating holders being made in a plurality of sections and one holder section carried by each of the said rst named upper and lower sections.

14. An electric heating unit comprising two plates provided with a series of Aopenu ings and stri s or bars Abetween said open- 2eings, said strips or bars having dependi portions spaced apart, insulating hoiVI positioned between the depending porticns of said bars .and an attenuated electric 1-esistance element held between the said ins lating holders and extending througne'zn device.

lVVitnees my hand this 22d dey of Me 1922 at the city of Milwaukee, in the eci of Milwaukee, State of Wisconsin.

WALTER C. L'NDEh/Lelll. 

